It is often desirable to measure power output of a bicyclist or a rider of other human powered vehicle. Such information is useful both for the casual rider as well as the high performance trainer. A bicyclist can use this information, among other things, to monitor increases in cardiovascular fitness, quantify maximum output and power, optimize pedaling cadence, and determine maximum efficiency. Such measurements are also useful to those seeking to reduce body fat though exercise or to replenish food during extended rides. While power measuring devices are available on stationary exercise equipment commonly found in health clubs and the like, the size of currently available power measuring devices makes it impractical to install them on actual human powered vehicles.
In addition to human powered vehicles, power measurements would also be useful for motor driven devices. For example, in motor assisted bicycles, chain tension and/or human power output can be used to determine the relative instantaneous output of the motor. For motor-driven devices such as motorcycles, chain tension and power output can be used to monitor the load on the engine, which relates information on fuel consumption, mechanical wear, and efficiencies.
What is needed then, is a method and device which is compact in size and operatively arranged to measure power output of a bicyclist.